/*
 * drivers/base/sync.c
 *
 * Copyright (C) 2012 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/debugfs.h>
//#include <linux/export.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/sync.h>
#include <linux/uaccess.h>

#include <linux/anon_inodes.h>

static void sync_fence_signal_pt(struct sync_pt *pt);
static int _sync_pt_has_signaled(struct sync_pt *pt);
static void sync_fence_free(struct kref *kref);
static void sync_dump(void);

static LIST_HEAD(sync_timeline_list_head);
static DEFINE_SPINLOCK(sync_timeline_list_lock);

static LIST_HEAD(sync_fence_list_head);
static DEFINE_SPINLOCK(sync_fence_list_lock);

struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
                                           int size, const char *name)
{
        struct sync_timeline *obj;
        unsigned long flags;

        if (size < sizeof(struct sync_timeline))
                return NULL;

        obj = kzalloc(size, GFP_KERNEL);
        if (obj == NULL)
                return NULL;

        kref_init(&obj->kref);
        obj->ops = ops;
        strlcpy(obj->name, name, sizeof(obj->name));

        INIT_LIST_HEAD(&obj->child_list_head);
        spin_lock_init(&obj->child_list_lock);

        INIT_LIST_HEAD(&obj->active_list_head);
        spin_lock_init(&obj->active_list_lock);

        spin_lock_irqsave(&sync_timeline_list_lock, flags);
        list_add_tail(&obj->sync_timeline_list, &sync_timeline_list_head);
        spin_unlock_irqrestore(&sync_timeline_list_lock, flags);

        return obj;
}
//EXPORT_SYMBOL(sync_timeline_create);

static void sync_timeline_free(struct kref *kref)
{
        struct sync_timeline *obj =
                container_of(kref, struct sync_timeline, kref);
        unsigned long flags;

        if (obj->ops->release_obj)
                obj->ops->release_obj(obj);

        spin_lock_irqsave(&sync_timeline_list_lock, flags);
        list_del(&obj->sync_timeline_list);
        spin_unlock_irqrestore(&sync_timeline_list_lock, flags);

        kfree(obj);
}

void sync_timeline_destroy(struct sync_timeline *obj)
{
        obj->destroyed = true;

        /*
         * If this is not the last reference, signal any children
         * that their parent is going away.
         */

        if (!kref_put(&obj->kref, sync_timeline_free))
                sync_timeline_signal(obj);
}
//EXPORT_SYMBOL(sync_timeline_destroy);

static void sync_timeline_add_pt(struct sync_timeline *obj, struct sync_pt *pt)
{
        unsigned long flags;

        pt->parent = obj;

        spin_lock_irqsave(&obj->child_list_lock, flags);
        list_add_tail(&pt->child_list, &obj->child_list_head);
        spin_unlock_irqrestore(&obj->child_list_lock, flags);
}

static void sync_timeline_remove_pt(struct sync_pt *pt)
{
        struct sync_timeline *obj = pt->parent;
        unsigned long flags;

        spin_lock_irqsave(&obj->active_list_lock, flags);
        if (!list_empty(&pt->active_list))
                list_del_init(&pt->active_list);
        spin_unlock_irqrestore(&obj->active_list_lock, flags);

        spin_lock_irqsave(&obj->child_list_lock, flags);
        if (!list_empty(&pt->child_list)) {
                list_del_init(&pt->child_list);
        }
        spin_unlock_irqrestore(&obj->child_list_lock, flags);
}

void sync_timeline_signal(struct sync_timeline *obj)
{
        unsigned long flags;
        LIST_HEAD(signaled_pts);
        struct list_head *pos, *n;

        spin_lock_irqsave(&obj->active_list_lock, flags);

        list_for_each_safe(pos, n, &obj->active_list_head) {
                struct sync_pt *pt =
                        container_of(pos, struct sync_pt, active_list);

                if (_sync_pt_has_signaled(pt)) {
                        list_del_init(pos);
                        list_add(&pt->signaled_list, &signaled_pts);
                        kref_get(&pt->fence->kref);
                }
        }

        spin_unlock_irqrestore(&obj->active_list_lock, flags);

        list_for_each_safe(pos, n, &signaled_pts) {
                struct sync_pt *pt =
                        container_of(pos, struct sync_pt, signaled_list);

                list_del_init(pos);
                sync_fence_signal_pt(pt);
                kref_put(&pt->fence->kref, sync_fence_free);
        }
}
//EXPORT_SYMBOL(sync_timeline_signal);

struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size)
{
        struct sync_pt *pt;

        if (size < sizeof(struct sync_pt))
                return NULL;

        pt = kzalloc(size, GFP_KERNEL);
        if (pt == NULL)
                return NULL;

        INIT_LIST_HEAD(&pt->active_list);
        kref_get(&parent->kref);
        sync_timeline_add_pt(parent, pt);

        return pt;
}
//EXPORT_SYMBOL(sync_pt_create);

void sync_pt_free(struct sync_pt *pt)
{
        if (pt->parent->ops->free_pt)
                pt->parent->ops->free_pt(pt);

        sync_timeline_remove_pt(pt);

        kref_put(&pt->parent->kref, sync_timeline_free);

        kfree(pt);
}
//EXPORT_SYMBOL(sync_pt_free);

/* call with pt->parent->active_list_lock held */
static int _sync_pt_has_signaled(struct sync_pt *pt)
{
        int old_status = pt->status;

        if (!pt->status)
                pt->status = pt->parent->ops->has_signaled(pt);

        if (!pt->status && pt->parent->destroyed)
                pt->status = -ENOENT;

        if (pt->status != old_status)
                pt->timestamp = ktime_get();

        return pt->status;
}

static struct sync_pt *sync_pt_dup(struct sync_pt *pt)
{
        return pt->parent->ops->dup(pt);
}

/* Adds a sync pt to the active queue.  Called when added to a fence */
static void sync_pt_activate(struct sync_pt *pt)
{
        struct sync_timeline *obj = pt->parent;
        unsigned long flags;
        int err;

        spin_lock_irqsave(&obj->active_list_lock, flags);

        err = _sync_pt_has_signaled(pt);
        if (err != 0)
                goto out;

        list_add_tail(&pt->active_list, &obj->active_list_head);

out:
        spin_unlock_irqrestore(&obj->active_list_lock, flags);
}

static int sync_fence_release(struct inode *inode, struct file *file);
static unsigned int sync_fence_poll(struct file *file, poll_table *wait);
static long sync_fence_ioctl(struct file *file, unsigned int cmd,
                             unsigned long arg);


static const struct file_operations sync_fence_fops = {
        .release = sync_fence_release,
        .poll = sync_fence_poll,
        .unlocked_ioctl = sync_fence_ioctl,
};

static struct sync_fence *sync_fence_alloc(const char *name)
{
        struct sync_fence *fence;
        unsigned long flags;

        fence = kzalloc(sizeof(struct sync_fence), GFP_KERNEL);
        if (fence == NULL)
                return NULL;

        fence->file = anon_inode_getfile("sync_fence", &sync_fence_fops,
                                         fence, 0);
        if (fence->file == NULL)
                goto err;

        kref_init(&fence->kref);
        strlcpy(fence->name, name, sizeof(fence->name));

        INIT_LIST_HEAD(&fence->pt_list_head);
        INIT_LIST_HEAD(&fence->waiter_list_head);
        spin_lock_init(&fence->waiter_list_lock);

        init_waitqueue_head(&fence->wq);

        spin_lock_irqsave(&sync_fence_list_lock, flags);
        list_add_tail(&fence->sync_fence_list, &sync_fence_list_head);
        spin_unlock_irqrestore(&sync_fence_list_lock, flags);

        return fence;

err:
        kfree(fence);
        return NULL;
}

/* TODO: implement a create which takes more that one sync_pt */
struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt)
{
        struct sync_fence *fence;

        if (pt->fence)
                return NULL;

        fence = sync_fence_alloc(name);
        if (fence == NULL)
                return NULL;

        pt->fence = fence;
        list_add(&pt->pt_list, &fence->pt_list_head);
        sync_pt_activate(pt);

        /*
         * signal the fence in case pt was activated before
         * sync_pt_activate(pt) was called
         */
        sync_fence_signal_pt(pt);

        return fence;
}
//EXPORT_SYMBOL(sync_fence_create);

static int sync_fence_copy_pts(struct sync_fence *dst, struct sync_fence *src)
{
        struct list_head *pos;

        list_for_each(pos, &src->pt_list_head) {
                struct sync_pt *orig_pt =
                        container_of(pos, struct sync_pt, pt_list);
                struct sync_pt *new_pt = sync_pt_dup(orig_pt);

                if (new_pt == NULL)
                        return -ENOMEM;

                new_pt->fence = dst;
                list_add(&new_pt->pt_list, &dst->pt_list_head);
                sync_pt_activate(new_pt);
        }

        return 0;
}

static int sync_fence_merge_pts(struct sync_fence *dst, struct sync_fence *src)
{
        struct list_head *src_pos, *dst_pos, *n;

        list_for_each(src_pos, &src->pt_list_head) {
                struct sync_pt *src_pt =
                        container_of(src_pos, struct sync_pt, pt_list);
                bool collapsed = false;

                list_for_each_safe(dst_pos, n, &dst->pt_list_head) {
                        struct sync_pt *dst_pt =
                                container_of(dst_pos, struct sync_pt, pt_list);
                        /* collapse two sync_pts on the same timeline
                         * to a single sync_pt that will signal at
                         * the later of the two
                         */
                        if (dst_pt->parent == src_pt->parent) {
                                if (dst_pt->parent->ops->compare(dst_pt, src_pt) == -1) {
                                        struct sync_pt *new_pt =
                                                sync_pt_dup(src_pt);
                                        if (new_pt == NULL)
                                                return -ENOMEM;

                                        new_pt->fence = dst;
                                        list_replace(&dst_pt->pt_list,
                                                     &new_pt->pt_list);
                                        sync_pt_activate(new_pt);
                                        sync_pt_free(dst_pt);
                                }
                                collapsed = true;
                                break;
                        }
                }

                if (!collapsed) {
                        struct sync_pt *new_pt = sync_pt_dup(src_pt);

                        if (new_pt == NULL)
                                return -ENOMEM;

                        new_pt->fence = dst;
                        list_add(&new_pt->pt_list, &dst->pt_list_head);
                        sync_pt_activate(new_pt);
                }
        }

        return 0;
}

static void sync_fence_detach_pts(struct sync_fence *fence)
{
        struct list_head *pos, *n;

        list_for_each_safe(pos, n, &fence->pt_list_head) {
                struct sync_pt *pt = container_of(pos, struct sync_pt, pt_list);
                sync_timeline_remove_pt(pt);
        }
}

static void sync_fence_free_pts(struct sync_fence *fence)
{
        struct list_head *pos, *n;

        list_for_each_safe(pos, n, &fence->pt_list_head) {
                struct sync_pt *pt = container_of(pos, struct sync_pt, pt_list);
                sync_pt_free(pt);
        }
}

struct sync_fence *sync_fence_fdget(int fd)
{
        struct file *file = fget(fd);

        if (file == NULL)
                return NULL;

        if (file->f_op != &sync_fence_fops)
                goto err;

        return file->private_data;

err:
        fput(file);
        return NULL;
}
//EXPORT_SYMBOL(sync_fence_fdget);

void sync_fence_put(struct sync_fence *fence)
{
        fput(fence->file);
}
//EXPORT_SYMBOL(sync_fence_put);

void sync_fence_install(struct sync_fence *fence, int fd)
{
        fd_install(fd, fence->file);
}
//EXPORT_SYMBOL(sync_fence_install);

static int sync_fence_get_status(struct sync_fence *fence)
{
        struct list_head *pos;
        int status = 1;

        list_for_each(pos, &fence->pt_list_head) {
                struct sync_pt *pt = container_of(pos, struct sync_pt, pt_list);
                int pt_status = pt->status;

                if (pt_status < 0) {
                        status = pt_status;
                        break;
                } else if (status == 1) {
                        status = pt_status;
                }
        }

        return status;
}

struct sync_fence *sync_fence_merge(const char *name,
                                    struct sync_fence *a, struct sync_fence *b)
{
        struct sync_fence *fence;
        int err;

        fence = sync_fence_alloc(name);
        if (fence == NULL)
                return NULL;

        err = sync_fence_copy_pts(fence, a);
        if (err < 0)
                goto err;

        err = sync_fence_merge_pts(fence, b);
        if (err < 0)
                goto err;

        /*
         * signal the fence in case one of it's pts were activated before
         * they were activated
         */
        sync_fence_signal_pt(list_first_entry(&fence->pt_list_head,
                                              struct sync_pt,
                                              pt_list));

        return fence;
err:
        sync_fence_free_pts(fence);
        kfree(fence);
        return NULL;
}
//EXPORT_SYMBOL(sync_fence_merge);

static void sync_fence_signal_pt(struct sync_pt *pt)
{
        LIST_HEAD(signaled_waiters);
        struct sync_fence *fence = pt->fence;
        struct list_head *pos;
        struct list_head *n;
        unsigned long flags;
        int status;

        status = sync_fence_get_status(fence);

        spin_lock_irqsave(&fence->waiter_list_lock, flags);
        /*
         * this should protect against two threads racing on the signaled
         * false -> true transition
         */
        if (status && !fence->status) {
                list_for_each_safe(pos, n, &fence->waiter_list_head)
                        list_move(pos, &signaled_waiters);

                fence->status = status;
        } else {
                status = 0;
        }
        spin_unlock_irqrestore(&fence->waiter_list_lock, flags);

        if (status) {
                list_for_each_safe(pos, n, &signaled_waiters) {
                        struct sync_fence_waiter *waiter =
                                container_of(pos, struct sync_fence_waiter,
                                             waiter_list);

                        list_del(pos);
                        waiter->callback(fence, waiter);
                }
                wake_up(&fence->wq);
        }
}

int sync_fence_wait_async(struct sync_fence *fence,
                          struct sync_fence_waiter *waiter)
{
        unsigned long flags;
        int err = 0;

        spin_lock_irqsave(&fence->waiter_list_lock, flags);

        if (fence->status) {
                err = fence->status;
                goto out;
        }

        list_add_tail(&waiter->waiter_list, &fence->waiter_list_head);
out:
        spin_unlock_irqrestore(&fence->waiter_list_lock, flags);

        return err;
}
//EXPORT_SYMBOL(sync_fence_wait_async);

int sync_fence_cancel_async(struct sync_fence *fence,
                             struct sync_fence_waiter *waiter)
{
        struct list_head *pos;
        struct list_head *n;
        unsigned long flags;
        int ret = -ENOENT;

        spin_lock_irqsave(&fence->waiter_list_lock, flags);
        /*
         * Make sure waiter is still in waiter_list because it is possible for
         * the waiter to be removed from the list while the callback is still
         * pending.
         */
        list_for_each_safe(pos, n, &fence->waiter_list_head) {
                struct sync_fence_waiter *list_waiter =
                        container_of(pos, struct sync_fence_waiter,
                                     waiter_list);
                if (list_waiter == waiter) {
                        list_del(pos);
                        ret = 0;
                        break;
                }
        }
        spin_unlock_irqrestore(&fence->waiter_list_lock, flags);
        return ret;
}
//EXPORT_SYMBOL(sync_fence_cancel_async);

static bool sync_fence_check(struct sync_fence *fence)
{
        /*
         * Make sure that reads to fence->status are ordered with the
         * wait queue event triggering
         */
        smp_rmb();
        return fence->status != 0;
}

int sync_fence_wait(struct sync_fence *fence, long timeout)
{
        int err = 0;

        if (timeout > 0) {
                timeout = msecs_to_jiffies(timeout);
                err = wait_event_interruptible_timeout(fence->wq,
                                                       sync_fence_check(fence),
                                                       timeout);
        } else if (timeout < 0) {
                err = wait_event_interruptible(fence->wq,
                                               sync_fence_check(fence));
        }

        if (err < 0)
                return err;

        if (fence->status < 0) {
                pr_info("fence error %d on [%p]\n", fence->status, fence);
                sync_dump();
                return fence->status;
        }

        if (fence->status == 0) {
                pr_info("fence timeout on [%p] after %dms\n", fence,
                        jiffies_to_msecs(timeout));
                sync_dump();
                return -ETIME;
        }

        return 0;
}
//EXPORT_SYMBOL(sync_fence_wait);

static void sync_fence_free(struct kref *kref)
{
        struct sync_fence *fence = container_of(kref, struct sync_fence, kref);

        sync_fence_free_pts(fence);

        kfree(fence);
}

static int sync_fence_release(struct inode *inode, struct file *file)
{
        struct sync_fence *fence = file->private_data;
        unsigned long flags;

        /*
         * We need to remove all ways to access this fence before droping
         * our ref.
         *
         * start with its membership in the global fence list
         */
        spin_lock_irqsave(&sync_fence_list_lock, flags);
        list_del(&fence->sync_fence_list);
        spin_unlock_irqrestore(&sync_fence_list_lock, flags);

        /*
         * remove its pts from their parents so that sync_timeline_signal()
         * can't reference the fence.
         */
        sync_fence_detach_pts(fence);

        kref_put(&fence->kref, sync_fence_free);

        return 0;
}

static unsigned int sync_fence_poll(struct file *file, poll_table *wait)
{
        struct sync_fence *fence = file->private_data;

        poll_wait(file, &fence->wq, wait);

        /*
         * Make sure that reads to fence->status are ordered with the
         * wait queue event triggering
         */
        smp_rmb();

        if (fence->status == 1)
                return POLLIN;
        else if (fence->status < 0)
                return POLLERR;
        else
                return 0;
}

static long sync_fence_ioctl_wait(struct sync_fence *fence, unsigned long arg)
{
        __s32 value;

        if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
                return -EFAULT;

        return sync_fence_wait(fence, value);
}

static long sync_fence_ioctl_merge(struct sync_fence *fence, unsigned long arg)
{
        int fd = get_unused_fd();
        int err;
        struct sync_fence *fence2, *fence3;
        struct sync_merge_data data;

        if (fd < 0)
                return fd;

        if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
                err = -EFAULT;
                goto err_put_fd;
        }

        fence2 = sync_fence_fdget(data.fd2);
        if (fence2 == NULL) {
                err = -ENOENT;
                goto err_put_fd;
        }

        data.name[sizeof(data.name) - 1] = '\0';
        fence3 = sync_fence_merge(data.name, fence, fence2);
        if (fence3 == NULL) {
                err = -ENOMEM;
                goto err_put_fence2;
        }

        data.fence = fd;
        if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
                err = -EFAULT;
                goto err_put_fence3;
        }

        sync_fence_install(fence3, fd);
        sync_fence_put(fence2);
        return 0;

err_put_fence3:
        sync_fence_put(fence3);

err_put_fence2:
        sync_fence_put(fence2);

err_put_fd:
        put_unused_fd(fd);
        return err;
}

static int sync_fill_pt_info(struct sync_pt *pt, void *data, int size)
{
        struct sync_pt_info *info = data;
        int ret;

        if (size < sizeof(struct sync_pt_info))
                return -ENOMEM;

        info->len = sizeof(struct sync_pt_info);

        if (pt->parent->ops->fill_driver_data) {
                ret = pt->parent->ops->fill_driver_data(pt, info->driver_data,
                                                        size - sizeof(*info));
                if (ret < 0)
                        return ret;

                info->len += ret;
        }

        strlcpy(info->obj_name, pt->parent->name, sizeof(info->obj_name));
        strlcpy(info->driver_name, pt->parent->ops->driver_name,
                sizeof(info->driver_name));
        info->status = pt->status;
        info->timestamp_ns = ktime_to_ns(pt->timestamp);

        return info->len;
}

static long sync_fence_ioctl_fence_info(struct sync_fence *fence,
                                        unsigned long arg)
{
        struct sync_fence_info_data *data;
        struct list_head *pos;
        __u32 size;
        __u32 len = 0;
        int ret;

        if (copy_from_user(&size, (void __user *)arg, sizeof(size)))
                return -EFAULT;

        if (size < sizeof(struct sync_fence_info_data))
                return -EINVAL;

        if (size > 4096)
                size = 4096;

        data = kzalloc(size, GFP_KERNEL);
        if (data == NULL)
                return -ENOMEM;

        strlcpy(data->name, fence->name, sizeof(data->name));
        data->status = fence->status;
        len = sizeof(struct sync_fence_info_data);

        list_for_each(pos, &fence->pt_list_head) {
                struct sync_pt *pt =
                        container_of(pos, struct sync_pt, pt_list);

                ret = sync_fill_pt_info(pt, (u8 *)data + len, size - len);

                if (ret < 0)
                        goto out;

                len += ret;
        }

        data->len = len;

        if (copy_to_user((void __user *)arg, data, len))
                ret = -EFAULT;
        else
                ret = 0;

out:
        kfree(data);

        return ret;
}

static long sync_fence_ioctl(struct file *file, unsigned int cmd,
                             unsigned long arg)
{
        struct sync_fence *fence = file->private_data;
        switch (cmd) {
        case SYNC_IOC_WAIT:
                return sync_fence_ioctl_wait(fence, arg);

        case SYNC_IOC_MERGE:
                return sync_fence_ioctl_merge(fence, arg);

        case SYNC_IOC_FENCE_INFO:
                return sync_fence_ioctl_fence_info(fence, arg);

        default:
                return -ENOTTY;
        }
}

#ifdef CONFIG_DEBUG_FS
static const char *sync_status_str(int status)
{
        if (status > 0)
                return "signaled";
        else if (status == 0)
                return "active";
        else
                return "error";
}

static void sync_print_pt(struct seq_file *s, struct sync_pt *pt, bool fence)
{
        int status = pt->status;
        seq_printf(s, "  %s%spt %s",
                   fence ? pt->parent->name : "",
                   fence ? "_" : "",
                   sync_status_str(status));
        if (pt->status) {
                struct timeval tv = ktime_to_timeval(pt->timestamp);
                seq_printf(s, "@%ld.%06ld", tv.tv_sec, tv.tv_usec);
        }

        if (pt->parent->ops->timeline_value_str &&
            pt->parent->ops->pt_value_str) {
                char value[64];
                pt->parent->ops->pt_value_str(pt, value, sizeof(value));
                seq_printf(s, ": %s", value);
                if (fence) {
                        pt->parent->ops->timeline_value_str(pt->parent, value,
                                                    sizeof(value));
                        seq_printf(s, " / %s", value);
                }
        } else if (pt->parent->ops->print_pt) {
                seq_printf(s, ": ");
                pt->parent->ops->print_pt(s, pt);
        }

        seq_printf(s, "\n");
}

static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
{
        struct list_head *pos;
        unsigned long flags;

        seq_printf(s, "%s %s", obj->name, obj->ops->driver_name);

        if (obj->ops->timeline_value_str) {
                char value[64];
                obj->ops->timeline_value_str(obj, value, sizeof(value));
                seq_printf(s, ": %s", value);
        } else if (obj->ops->print_obj) {
                seq_printf(s, ": ");
                obj->ops->print_obj(s, obj);
        }

        seq_printf(s, "\n");

        spin_lock_irqsave(&obj->child_list_lock, flags);
        list_for_each(pos, &obj->child_list_head) {
                struct sync_pt *pt =
                        container_of(pos, struct sync_pt, child_list);
                sync_print_pt(s, pt, false);
        }
        spin_unlock_irqrestore(&obj->child_list_lock, flags);
}

static void sync_print_fence(struct seq_file *s, struct sync_fence *fence)
{
        struct list_head *pos;
        unsigned long flags;

        seq_printf(s, "[%p] %s: %s\n", fence, fence->name,
                   sync_status_str(fence->status));

        list_for_each(pos, &fence->pt_list_head) {
                struct sync_pt *pt =
                        container_of(pos, struct sync_pt, pt_list);
                sync_print_pt(s, pt, true);
        }

        spin_lock_irqsave(&fence->waiter_list_lock, flags);
        list_for_each(pos, &fence->waiter_list_head) {
                struct sync_fence_waiter *waiter =
                        container_of(pos, struct sync_fence_waiter,
                                     waiter_list);

                seq_printf(s, "waiter %pF\n", waiter->callback);
        }
        spin_unlock_irqrestore(&fence->waiter_list_lock, flags);
}

static int sync_debugfs_show(struct seq_file *s, void *unused)
{
        unsigned long flags;
        struct list_head *pos;

        seq_printf(s, "objs:\n--------------\n");

        spin_lock_irqsave(&sync_timeline_list_lock, flags);
        list_for_each(pos, &sync_timeline_list_head) {
                struct sync_timeline *obj =
                        container_of(pos, struct sync_timeline,
                                     sync_timeline_list);

                sync_print_obj(s, obj);
                seq_printf(s, "\n");
        }
        spin_unlock_irqrestore(&sync_timeline_list_lock, flags);

        seq_printf(s, "fences:\n--------------\n");

        spin_lock_irqsave(&sync_fence_list_lock, flags);
        list_for_each(pos, &sync_fence_list_head) {
                struct sync_fence *fence =
                        container_of(pos, struct sync_fence, sync_fence_list);

                sync_print_fence(s, fence);
                seq_printf(s, "\n");
        }
        spin_unlock_irqrestore(&sync_fence_list_lock, flags);
        return 0;
}

static int sync_debugfs_open(struct inode *inode, struct file *file)
{
        return single_open(file, sync_debugfs_show, inode->i_private);
}

static const struct file_operations sync_debugfs_fops = {
        .open           = sync_debugfs_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

int sync_debugfs_init(void)
{
        debugfs_create_file("sync", S_IRUGO, NULL, NULL, &sync_debugfs_fops);
        return 0;
}
//late_initcall(sync_debugfs_init);

#define DUMP_CHUNK 256
static char sync_dump_buf[64 * 1024];
void sync_dump(void)
{
       struct seq_file s = {
               .buf = sync_dump_buf,
               .size = sizeof(sync_dump_buf) - 1,
       };
       int i;

       sync_debugfs_show(&s, NULL);

       for (i = 0; i < s.count; i += DUMP_CHUNK) {
               if ((s.count - i) > DUMP_CHUNK) {
                       char c = s.buf[i + DUMP_CHUNK];
                       s.buf[i + DUMP_CHUNK] = 0;
                       pr_cont("%s", s.buf + i);
                       s.buf[i + DUMP_CHUNK] = c;
               } else {
                       s.buf[s.count] = 0;
                       pr_cont("%s", s.buf + i);
               }
       }
}
#else
static void sync_dump(void)
{
}
#endif